I am experimenting once again with using a computer, its sound card and MixW to perform some RTTY, PSK and other digital modes. Somewhere I have a transformer isolated homebrew adapter made up, but have been examining what new possibilities are offered by my new Icom IC-746.

So I am in the usual evaluation of buy vs. build an adapter. I like to build my adapters, but realize the commercial offerings range from almost too cheap to very expensive.

Anyway, while I figure out what do to, I still wanted to get my computer set up with at least a receive capability so I can see if MixW works. I realized quick all I needed to get sound into the computer was a cheapo computer microphone. These are the roundish units that cost about $8 at Wal-Mart. Radio Shack use to have a model, but I was told they discontinued it and another similar model (black not white like the previous model) is coming soon. It looks something like…

mic.jpg

Anyway, the point is while you evaluate what sound card interfacing is appropriate for your radio, get a cheapo computer mic, plug it in, position it near your radio’s speaker and start decoding those digital and other modes with your MixW or similar program.

So far using this simple mic stuck near the IC-746 speaker allows easy reception of PSK, RTTY and CW.

Make sure you plug this into a computer “MIC” input, not a line input. Many of these microphones need the DC power supplied by the “ring” of the tip-ring-sleeve connections.

Update…

cheapmic.png

On New Year’s Eve I tried using my Rig’s microphone to pick up the PSK tones from the computer’s speaker to see if I could close the loop. I had to fiddle with mic gain and rf power to get the tone modulating the radio while not increasing the ALC. After just a little adjustment I had a successful QSO from Virginia to Nevada on 20M PSK in the middle afternoon EST. He was able to hear me better than I him. I could barely hear his signal so I cannot be sure if it was simply a weak signal or something about my cheapo computer microphone or both.

Room for improvement is clear, but the point is you can do digital modes with your computer and rig right now without any connection cables using stock equipment by simply adding a cheap mic to your computer. Yes you will have to manage the transmit switch on your rig manually and also put the sound card software, like MixW, into TX mode manually, but this is really not so bad.

For those of you on the fence on your next sound card radio interface do the above and take your time. You will probably make a better choice after you operated in the raw above for a while.

Being a ham radio operator sometimes forces us to operate from many different locations. We frequently wind up logging our contacts on many different computers. Later we find ourselves with the task of combining our logs into one big log so we can check our standings of whatever it might be we care about: WAS, WAZ, etc.

Over the years I have settled on a method which seems to work quite well. Instead of logging to different files on each computer, I “move” the active log file from one computer to the next using CVS as an intermediate data storage point.

For those not familiar with CVS, it is a software revision control and management system which provides a central organized spot where many developers can work on files separately, but in a controlled fashion which benefits all.

CVS has many features, but the most important feature for our ham logs is its ability to function as a central server. Each logging computer has a CVS client installed. Whenever I wish to log to a certain computer, I update the file(s) to my local machine using the CVS client tool. When this happens the local copy of the file is freshened up with the very latest version of the file(s). Once this is done, I close CVS, open the logging program and viola my latest contacts are right there ready for new QSOs.

As I make QSOs, the local copy of the file(s) change. Once I am done with operating, I commit the file(s) back to the CVS server where they become the next numerical revision.

If I need to operate on any computer I simply update the local log file(s) to make sure I have the latest revision and off I go.

Using CVS or any of its cousins (Subversion is good) allows you to manage one file in multiple locations relieving you of merging log data later. Plus you get the benefit of many computers having some past version of your data so if disaster strikes, you can recover at least some if not all your data.

CVS or any server based revision control system is not for everyone, but for me the system works quite well. One interesting advantage I found is when I am away from home, but suddenly find myself operating at guest radio accommodations. If I don’t have my laptop with me, but have access to another computer I can download N3FJP ACLog, load it up, download a CVS client, grab the latest data file(s) and be off and running with my latest contacts. This, of course, assumes you have access to the Internet. However, you only need network connectivity during the file transfers; Once you have the files, CVS and networking are out of the picture.

One serious advantage I have is my own server on the Internet where I host some CVS data. You can just as easily put a CVS server on your Windows box on your private network if you do not wish to access the data from the Internet. A good CVS server for Windows is CVSNT.

It even makes sense to use CVS if you never switch machines to take snapshots of your log files incrementing as you go. This enables you to revert back to a previous revision of your logs should you somehow destroy your current log. Being able to revert back to a working revision of any kind of file is a very nice thing; It has saved my bacon numerous times.

Of the many ways to organize your single or multiple log files, CVS has totally solved the problem for me.

I finally got my copper pipe J-Pole up on a modest mount and cabled into my ham shack. It works, but I stumbled into many interesting things that most folks seem to ignore. In addition to the many J-Pole tutorials on the Internet you should also consider: More »

Here is a great tool for RF Analysis which:

  • Deals with diffraction effects,
  • Computes the Fresnel effects,
  • Handles elevation data from many different sources

RF Links have many issues that plaque all too many folks in charge of ensuring radios work as planned. A tool like this provides this kind of view…

radiomobile.png

With this tool you can understand why some RF links actually fade even when the two antennas are in complete view of each other. When the wavelengths get longer than light wild things happen. The program is free and, from what I can tell so far, works very well.

http://www.cplus.org/rmw/english1.html

In the past few months I have been testing antennas and antenna ground systems for a series of articles on the main part of this web site…

http://www.cosjwt.com/

One piece of equipment which proved absolutely essential is the antenna analyzer from MFJ Enterprises. I have the older cousin of the MFJ-259B pictured here…

mfj-259b.jpg

More »

When feeding a J-Pole is obviously makes sense to install a choke balun to ensure the outside of the coax shield does not conduct energy down the coax thus degrading the antenna pattern via additional radiator area. This article nicely discusses using beads to achieve the goal: More »

Recently I specified some cables and connectors for an antenna system we are putting together at work. I stumbled across this…

http://www.eham.net/articles/5300

There are some good thoughts in there and, quite obviously, some belief systems in place.

For the average ham with max power on HF and something less on bands above 50MHz the following points worth consideration include: More »

I have been purchasing some used ham radio equipment from Ebay and decided to see what the Kenwood TS-2000 transceivers are going for on the used market. I discovered they are holding their value quite well… a bit too well actually.
More »

During construction of a vertical antenna in my back yard, I wondered if the popular suggestion that ground rods are essential to good RF performance and antenna efficiency even if you have a system of radials was true.

The answer appears to be no. Visit…

http://www.cosjwt.com/index.php?a=21

…for more information.

TenTec Omni VII

A fellow wrote an excellent summary of some possible ways to control a TenTec Omni VII radio from the Internet. Here is the link…
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